JP2017094442A - Machining apparatus and machining method using superconductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide machining that has flexibility and that is applicable to complex product shapes by trapping a magnet functioning as a tool at a fixed place through a pin retention effect to eliminate the necessity of cooling the tool and a machined part itself.SOLUTION: A cooled superconductor is housed and fixed in a heat-insulated container installed on a rotary-driven rotary table or a vibration-driven vibration table. A magnet functioning as a tool is arranged adjacently to the superconductor and, during a machining operation, the magnet is driven accompanying the rotary-driven or vibration-driven superconductor while retaining the magnet at the position of a fixed height from a superconductor and floating the magnet by using the pin retention effect of the superconductor. A workpiece is machined by controlling feeding of at least one of the workpiece and the superconductor.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a processing apparatus and a processing method using a superconductor. The present invention can be applied to technical fields related to production processing such as cutting, grinding, and polishing. Production processing technology is a necessary elemental technology for all machines, and can be applied to many fields from machine tool field to automobile, aviation field, transportation, robot, and architecture. Further, the present invention is effective in technical fields such as hollow machining, which is difficult in the prior art, because the tool floats in the air, and unlike the conventional production machining, there is no restriction on the machining shape due to tool interference.

  Cutting, grinding, lapping, polishing, etc. have been put to practical use as conventional processing techniques. As a machine tool for performing these removal processes, what is common to all processing methods is that it is physically difficult such as hollow processing because the tool is pressed from the outside of the work piece and pressed from the surface of the work piece to push the tool from the surface. It is. On the other hand, electrochemical processing, particle beam processing, laser processing, etc. have been put to practical use as special processing. Although it is possible to selectively process a deep hole portion with respect to these processing methods, it is difficult to perform hollow processing into a complicated shape. With regard to the hollow processing technology, applications such as magnetically assisted processing have been reported in recent years. However, since this technology attracts magnetic particles by magnetic force, processing in piping is limited. Therefore, in spite of the need for hollow machining, the present situation is that the machining technique itself has not been devised.

  On the other hand, superconducting technology has been put to practical use in high-speed trains such as linear motor cars. Superconducting technology has the diamagnetic nature of superconductivity, and can be levitated about 10 cm by introducing a superconducting material. Therefore, unlike the normal linear motor car introduced at the Aichi Expo, it is possible to travel at high speed and safely. Although these superconducting technologies mainly require cooling to the liquid helium temperature, many high-temperature superconducting materials such as YBCO have been proposed in recent years. So far, the present inventors have proposed that processing is performed by utilizing attraction force by strong magnetization by superconducting in a magnetic field (see Non-Patent Document 1). However, the method using the attractive force as disclosed in Non-Patent Document 1 cannot be applied to a complicated shape by using only the attractive force basically as in the case of magnetically assisted processing. Further, in the technique disclosed in Non-Patent Document 1, since the tool needs to be cooled to a low temperature, a structure such as a cooling mechanism is complicated.

FIG. 10A is a diagram for explaining a processing technique using the superconductor disclosed in Non-Patent Document 1, and FIG. 10B is a diagram for explaining a pinning effect used in the processing technique. (C) is a figure explaining a magnet structure. A magnet was fixed to the inner bottom portion of the heat insulating container supported by a jack on the XY stage, and a Cu plate was set as a workpiece on a support bar independent of the XY stage. Furthermore, a YBCO bulk is installed thereon, and the inside of the heat insulating container is filled with liquid nitrogen, thereby superconducting the YBCO bulk. The YBCO bulk is prepared by mixing and baking the yttrium-based superconductor YBa ₂ Cu ₃ O ₇ raw materials. Due to the pinning effect in the superconducting state, the YBCO bulk is kept in place from the magnet. The position of the magnet is moved up and down by a jack, and is moved in the horizontal XY direction by an XY stage.

  As a result, as shown in FIG. 10B, the distance between the magnet and the superconductor is kept in a certain range by a known pinning effect. The pinning effect is a phenomenon in which the magnetic flux is trapped in the normal conduction part of the strain or impurities (pins) inside the superconductor and stops moving as if pinned. Thereby, even if the magnet is moved up, down, left and right, the superconductor (YBCO bulk) follows the moving magnet and is always maintained at a constant height from the magnet. For example, when the magnet moves in the vertical and horizontal directions, the YBCO bulk moves in the vertical and horizontal directions relative to the Cu plate fixed to the support rod. If the YBCO bulk surface can be processed as a tool, the Cu plate surface can be cut.

  However, it is necessary to cool the workpiece to be cut by the YBCO bulk and the tool whose surface is processed using liquid nitrogen in the heat insulating container. In addition, as shown in FIG. 10C, the magnet used here has S and N poles arranged in the vertical direction. When this magnet rotates, the tool (YBCO bulk) itself rotates, but the rotational force is very weak, so if it touches lightly, it continues to rotate, but the tool stops only by slightly increasing the contact pressure. There was a problem. Therefore, in order to apply to actual processing, it is necessary to apply a high rotational force to the tool.

Hirotaka Hidaka, Keito Suzuki, et al., “Research on magnetic-assisted processing technology using superconductors”, Transactions of the Japan Society of Mechanical Engineers No158-1 pp347-pp348, March 2015

  In conventional machining methods, drills and lathes press the tool against the workpiece and rotate and translate the tool with power from the outside to realize machining at the contact part of the tool. Was difficult. For this reason, when product shapes such as inner surface processing of molds and medical devices and frame formation processing of automobiles and airplanes become complicated, after parts are deeply digged and grooved, It was necessary to connect them together. Here, because there are many restrictions such as work materials and joining methods, it was difficult to manufacture a product having a complicated hollow shape.

  Furthermore, regarding the driving force of the floating tool, the method of Non-Patent Document 1 (see FIG. 10) is a method that uses an attractive force that is strongly magnetized by superconductivity in a magnetic field, and actually uses only the attractive force. It cannot be applied to complex shapes.

  In the present invention, a magnet functioning as a tool, not a superconductor, is trapped in a certain place by a pinning effect, so that it is not necessary to cool the tool and the work part itself, and the work piece is kept at room temperature. The purpose is to realize machining that is flexible and can be applied to complex product shapes.

  Another object of the present invention is to obtain a sufficient driving force by devising the arrangement of magnet polarities. In the rotational movement of the tool, when a floating tool is pressed onto the work surface, a force that impedes the movement of the tool due to frictional force acts. At this time, if the driving force of the tool is low, the tool itself cannot move due to this frictional force, so that sufficient machining cannot be performed. According to the present invention, such a problem can be solved.

  The processing apparatus and the processing method of the present invention perform processing by pressing a tool that rotates or vibrates against the workpiece held by the holding means. A cooled superconductor is accommodated and fixed in a heat-insulated container installed on a rotating table or a vibration table that is driven to rotate. A magnet that functions as a tool is placed adjacent to this superconductor, and the pinning effect of the superconductor is used during machining operations to keep the magnet at a certain height from the superconductor. The magnet is driven following the superconductor that is driven to rotate or vibrate while floating. A feed unit configured to move at least one of the workpiece and the superconductor in at least one of a horizontal plane direction parallel to the superconductor surface and a vertical direction perpendicular to the horizontal plane; And the workpiece is processed by controlling the feed of at least one of the superconductors.

  The feeding means configured to move the workpiece or the superconductor is configured by combining an XY stage that can move in two orthogonal directions in a horizontal plane and a Z stage that can move in the vertical direction. The processing of the workpiece is cutting or surface polishing using an abrasive.

The superconductor is preferably YBCO bulk prepared by mixing and baking the yttrium-based superconductor YBa ₂ Cu ₃ O ₇ raw materials. The magnet shape is a donut shape, a disk shape, a rectangular shape, or a cylindrical shape. The magnet has two, four, or more S and N poles arranged on the same plane. A plurality of magnets can be arranged on the same surface, and the force with which these magnets work can be used. The magnet functioning as a tool is configured by fixing abrasive grains for processing on the magnet surface, or affixing a metal plate having a tool shape on the surface, or processing the magnet surface into a blade shape.

  According to the present invention, by utilizing the pinning effect of the superconductor, it is possible to perform processing while the tool is levitated to a certain place in the air.

  According to the present invention, while utilizing the pinning effect, it is possible to perform processing at room temperature without the need to cool the tool and the work piece, and the hollow and complicated shape that has been difficult with the conventional processing method Can be realized. In addition, since the present invention can be processed at room temperature, an improvement in processing efficiency can be expected by using a dedicated liquid such as an abrasive other than the step of cutting with a floating tool.

  Further, according to the present invention, it is effective for grinding, lapping and polishing of the inner surface of a structure which has already been once hollow, such as a mold. In particular, when the magnet is suspended in the air, the processing area is at a temperature higher than room temperature, so that it is effective to use a polishing liquid as in the past.

  Since the machining technology of the present invention is an indispensable technology in a wide range of fields such as transportation equipment such as automobiles, electronic equipment, MEMS, medical care, and housing, the applicable fields can be greatly expanded.

  In the medical field, in addition to the application of medical devices such as endoscopes by hollow processing, a spherical tool part that is levitated in the air is inserted into the body as a scalpel, and the affected part such as a tumor or thrombus is selectively excised and captured. Therefore, it can be applied to treatment methods that have been impossible in conventional medicine.

  In the automotive field and the aircraft field, it is possible to reduce the thickness by hollow processing the thick part of the engine part and the frame, and it is possible to reduce the weight while maintaining the strength.

  In the MEMS field, conventionally, grooves have been processed by a semiconductor process such as dry etching, and substrates are bonded together to form a liquid flow path, which has been applied to microreactors for the production of new drugs and catalysts. In the present invention, it is not necessary to bond the liquid flow paths by hollow processing, and processing can be performed in a single step. For example, it can be applied to the production of micromotors, microactuators, microreactors and the like.

It is a schematic block diagram which shows the 1st example which applied the processing apparatus comprised based on this invention to the process by the movement of a workpiece (workpiece). It is a schematic block diagram which shows the 2nd example which applied the processing apparatus comprised based on this invention to the process by the movement of a processing tool. It is a schematic block diagram which shows the 3rd example which applied the processing apparatus comprised based on this invention to the vibration processing by a vibrator | oscillator. It is a figure explaining the magnetic floating system using the pinning effect utilized for the processing technique of this invention. It is a figure explaining the single-sided dipole magnet as a 1st example of the magnet structure which can be used in the processing apparatus comprised based on this invention. It is a figure explaining a single-sided quadrupole magnet as a 2nd example of the magnet structure which can be used in the processing apparatus comprised based on this invention. It is a figure explaining the case where a several magnet is used. It is a schematic block diagram of the processing apparatus used for the hollow L-shaped process experiment, (a) And (b) has shown the 1st and 2nd step of the L-shaped process, respectively. It is the photograph (A) seen from the upper surface of the superconductor shown in FIG. 8, and a magnet part, and the photograph (B) of the workpiece after a process. (A) is a figure explaining the processing technique using the superconductor of a nonpatent literature 1, (B) is a figure explaining the pinning effect utilized for the processing technique, (C () Is a figure explaining a magnet structure.

  Hereinafter, the present invention will be described based on examples. FIG. 1 is a schematic configuration diagram showing a first example in which a processing apparatus configured according to the present invention is applied to processing by movement of a workpiece (workpiece). In FIG. 1, a superconductor cooled with liquid nitrogen or cold gas is accommodated and fixed in a heat insulating container (for example, made of polystyrene foam) installed on a turntable rotated by a motor. A magnet that functions as a circular tool is disposed adjacent to the superconductor. During the machining operation, this magnet stays at a certain height from the superconductor and floats by utilizing the pinning effect of superconductivity. As described above, although the superconductor needs to be cooled, since the magnet and the workpiece can be processed at room temperature, it can be used in combination with abrasives, so that the processing efficiency can be improved. I can expect.

  The workpiece is independent of the rotationally driven superconductor and the magnet (circular tool) driven following it, and is orthogonal to the superconductor surface in the X, Y, and horizontal planes. It is possible to feed in at least one of the vertical directions (Z direction) orthogonal to the direction. The workpiece feeding means is realized by combining a frame, an XY stage, and a Z stage. As a processing method, a workpiece is processed by controlling the feed with an XY stage and a Z stage with respect to a magnet (circular tool) driven following a superconductor that is rotationally driven.

  FIG. 2 is a schematic configuration diagram showing a second example in which the machining apparatus constructed according to the present invention is applied to machining by moving a machining tool. The second example shown in FIG. 2 is an XY that enables a rotationally driven superconductor to move further in at least one of a horizontal plane direction (X direction, Y direction) and a vertical direction (Z direction). It differs from the first example shown in FIG. 1 only in that a stage and a Z stage are added. The X-Y stage and the Z stage constitute a superconductor feeding means. In this way, it is necessary to provide a feed means that enables the rotationally driven superconductor or at least one of the workpieces to move in at least one of the X direction, the Y direction, and the Z direction. It is not always necessary to prepare for both. Therefore, in the second example shown in FIG. 2, it is not always necessary to provide a feed means that can move the workpiece in the X, Y, and Z directions, and the workpiece is independent of the superconductor. It may be fixed directly to the frame to be fixed.

  FIG. 3 is a schematic configuration diagram showing a third example in which the processing apparatus configured according to the present invention is applied to vibration processing using a vibrator. The third example shown in FIG. 3 differs from the first example shown in FIG. 1 in which the superconductor is rotationally driven, only in that a vibration mechanism using a vibrator is provided. The vibration mechanism is configured by a vibration table coupled to a vibrator that is driven to vibrate using an electromagnet or the like, for example. As with the first example, a superconductor cooled with liquid nitrogen or cold gas is accommodated and fixed in a heat insulating container (for example, made of polystyrene foam) installed on the shaking table.

  The workpiece in the present invention can be applied to all materials other than ferromagnetic materials. For example, stainless steel (except for ferromagnetic materials), aluminum, copper, brass, and resins are targeted. Here, in addition to cutting, surface polishing can be performed by using an abrasive. In addition, complex shapes have been developed with the progress of modeling techniques such as 3D printers and additive manufacturing, but no means for improving the surface properties after modeling has been established. Therefore, by applying the surface grinding or polishing technique according to the present invention, it is possible to improve the surface properties such as the surface and the inner surface of the shaped article.

  In the first example, the second example, and the third example, when processing, the workpiece is relatively moved with respect to the circular tool in the X direction, the Y direction, and the Z direction while the circular tool is trapped in a certain place. Move in at least one of the directions. The relative movement of the workpiece with respect to the circular tool is not necessarily performed by moving the workpiece, and the superconductor that the tool follows may be moved while the workpiece is fixed. This circular tool can be hollowed by applying a rotational motion or vibration.

  In the first example, the second example, and the third example, the entire processing apparatus including the superconductor, the magnet, the workpiece, and the supporting means thereof can be processed in a state of being inverted upside down. In this case, the magnet is disposed adjacent to the superconductor, and stays at a certain height from the superconductor and floats below the superconductor during the processing operation.

  Since the rotational movement or vibration of the circular tool follows the movement of the superconductor, it is performed by applying the rotational movement or vibration to the superconductor. Thus, by controlling the motion trajectory of the superconductor, it becomes possible to process a hollow and complicated shape. However, the processing technique of the present invention may also perform cutting, grinding, lapping, polishing, etc., in which the tool is pressed from the outside and the processing proceeds from the surface of the workpiece, as is the case with conventional processing techniques. Is possible.

  FIG. 4 is a diagram for explaining a magnetic floating system using a pinning effect used in the processing technique of the present invention. Although the pinning effect is known per se as described with reference to FIG. 10B, the present invention uses the arrangement of the superconductor and the magnet opposite to FIG. 10B. To do. This pinning effect keeps the distance between the magnet and the superconductor within a certain range. In FIG. 4, it is a superconductor that controls the movement trajectory, and a magnet that functions as a tool is maintained at a constant height from this superconductor. As a result, there is no need to cool the tool and the processed part itself, and processing at room temperature is possible. Furthermore, since not only the suction force of the tool with respect to a to-be-processed part but pressing force can also be utilized, the process of a complicated shape is attained.

  There are two types of superconductors: type 1 superconductors and type 2 superconductors due to the difference in magnetic field reaction. It is also a feature of the type 2 superconductor that a pinning effect occurs when magnetic flux enters the superconductor. The pinning effect utilized by the present invention is a phenomenon in which magnetic flux is trapped by normal conduction parts such as strains and impurities inside the type II superconductor and does not move as if pinned. This phenomenon is not seen in Type 1 superconductors that completely eliminate magnetic flux.

The superconductor used in the present invention is desirable because the YBCO bulk produced by mixing and baking the yttrium-based superconductor YBa ₂ Cu ₃ O ₇ raw material can be superconducted with low-cost liquid nitrogen. . However, a superconductor made of an alloy or a compound, a copper oxide high temperature superconductor, or a second type superconductor such as niobium (Nb) and vanadium (V) can be used. Irregularly creating defects by irradiating bulk superconductors with heavy particle beams or introducing impurities, trapping magnetic flux in these defects, and superconducting thin films with triangular lattices by lithography and etching There have been known methods for opening countless holes (anti-dots).

  FIG. 5 is a diagram illustrating a single-sided dipole magnet as a first example of a magnet configuration that can be used in a machining apparatus configured according to the present invention. The magnet shape is a donut shape or a disk shape as illustrated. However, as shown in FIG. 3, when cutting by vibration, the magnet shape may be rectangular or cylindrical. Rotating motion can be driven by arranging two or four poles (see FIG. 6) or more S poles or N poles on the same plane. When the polarities are the same with respect to the direction of rotation or vibration as in the prior art, the tool itself floats, but it is difficult to obtain a driving force, so it is preferable that magnetic bodies having different polarities exist at least in the same plane. A circular tool can be cut by applying vibration or rotational motion. At the time of machining, the workpiece is slid to the machining method with the tool trapped in a certain place. By controlling this movement trajectory, it is possible to perform processing that is hollow and capable of a complicated shape.

  In the case of the single-sided bipolar shown in FIG. 5, rotational driving in the θ direction is possible, but rotational driving in the Φ direction is not possible. However, a degree of freedom also occurs with respect to rotation due to an external force in the Φ direction about the boundary between the S pole and the N pole. Therefore, followability occurs in the Φ direction.

  As the magnet, a neodymium magnet, a samarium cobalt magnet, an anisotropic ferrite magnet or the like is preferable. In addition, the tool itself includes a type in which abrasive grains for processing are fixed on the magnet surface and a type in which a metal plate having a tool shape on the surface is attached to the surface. For soft materials such as resin, a method of processing the magnet surface into a blade shape is also possible.

  FIG. 6 is a diagram illustrating a single-sided quadrupole magnet as a second example of a magnet configuration that can be used in a processing apparatus configured according to the present invention. It differs from the first example shown in FIG. 5 only in that the number of poles is four. As illustrated, when there are four or more poles in the horizontal plane, not only the rotation drive in the θ direction but also the rotation drive in the Φ direction is possible. The prior art in the table of FIG. 6 shows the magnetic pole arrangement shown in FIG.

  FIG. 7 is a diagram for explaining a case where a plurality of magnets are used, in which (A) shows before processing, and (B) shows after processing. As shown in FIG. 7A, a plurality of (illustrated as two) magnets are arranged on the same plane. Depending on the arrangement of the S pole and N pole of a plurality of floating magnets, the magnets attract each other or repel each other. Here, by simply using the force of this magnet in addition to the pinning force, for example, as shown in FIG. 7B, a cylindrical workpiece can be processed into a conical shape.

  It was confirmed by experiment that hollow L-shaped processing is possible with the processing apparatus configured according to the present invention. Hereinafter, the experimental results will be described with reference to FIG. 8 showing the outline of the apparatus used in the experiment and FIG. 9 which is a photograph of the workpiece after hollow machining.

  FIG. 8 is a schematic configuration diagram of the processing apparatus used in the hollow L-shaped processing experiment, and (a) and (b) show the first and second steps of the L-shaped processing, respectively. As in the example shown in FIG. 1, a superconductor cooled with liquid nitrogen is accommodated and fixed in a heat insulating container installed on a turntable, and a magnet functioning as a circular tool is placed above the superconductor. Be placed. During the machining operation, this magnet is levitated to a certain height position from the superconductor by utilizing the pinning effect of superconductivity.

  In the first step of machining the workpiece in the vertical direction, the workpiece is moved so as to be pressed against the circular tool while the circular tool is trapped in a certain place. The circular tool cuts off the cutting portion shown in the figure by applying vibration and rotational motion. Next, in a state where the tool is in the cutting part, the workpiece is horizontally fed as a second step. By these first and second steps, it becomes possible to perform hollow L-shaped processing.

FIG. 9 is a photograph (A) seen from the top surface of the superconductor and magnet part shown in FIG. 8, and a photograph (B) of the workpiece after processing. In this experimental apparatus, a heat insulating container made of foamed polystyrene is fixed on a turntable made of a metal bottom on a disk. The superconductor YBCO is inserted into it. In this experiment, four superconductor bulks having a diameter of 15 mm square and a thickness of about 10 mm were arranged in this experiment. The size of the superconducting bulk depends on the size of the workpiece. On top of that, liquid nitrogen is injected into the heat insulating container while holding the neodymium magnet in the air. And after a magnet traps by pinning, a magnet is also rotated by rotating a turntable. The rotation speed at this time is 60 rotations. A paper file was affixed to the surface of the floating magnet, and processing was performed using this grindstone. The size of the magnet is about 20mm in diameter. FIG. 9B shows the workpiece after processing. In this experiment, the processing was performed using a square column foamed polystyrene, but in FIG. 9B, the holes formed by the processing can be confirmed. The hole dimensions at this time are equivalent to the diameter and thickness of the magnet. Therefore, it was confirmed that the hole was formed according to the trajectory of the magnet. In addition, here, when the magnet was inserted into the foamed polystyrene during machining, it was confirmed that the machining progressed similarly reflecting the movement of the workpiece even when it moved vertically.

Claims (9)

In a processing apparatus for processing a workpiece by pressing a tool that rotates or vibrates against the workpiece held by a holding means,
The cooled superconductor is housed and fixed in a heat-insulated container installed on a rotating table or a vibration table that is driven to rotate,
A magnet functioning as the tool is disposed adjacent to the superconductor, and the magnet is moved from the superconductor to a certain height by using the pinning effect of the superconductor during processing operation. Driving the magnet following the superconductor that is driven to rotate or vibrate while staying in position and floating,
A feed means configured to move at least one of the workpiece and the superconductor in at least one of a horizontal plane direction parallel to the superconductor surface and a vertical direction perpendicular to the horizontal plane;
A processing apparatus for processing the workpiece by controlling feeding of at least one of the workpiece and the superconductor. The feeding means configured to move the workpiece or the superconductor is configured by combining an XY stage that can move in two orthogonal directions in the horizontal plane and a Z stage that can move in the vertical direction. The processing apparatus according to claim 1. The processing apparatus according to claim 1, wherein the processing of the workpiece is cutting or surface polishing using an abrasive. _2. The processing apparatus according to claim 1, wherein the superconductor is a YBCO bulk prepared by mixing and baking yttrium-based superconductor YBa ₂ Cu ₃ O ₇ raw materials. The processing apparatus according to claim 1, wherein the magnet shape is a donut shape, a disk shape, a rectangular shape, or a columnar shape. The processing apparatus according to claim 1, wherein the magnet has two poles, four poles, or more S poles and N poles arranged on the same plane. The processing apparatus according to claim 1, wherein a plurality of the magnets are arranged on the same surface, and a force by which the plurality of magnets interact with each other is used. The magnet functioning as the tool is configured by fixing processing abrasive grains on the magnet surface, or by pasting a metal plate having a tool shape on the surface, or processing the magnet surface into a blade shape. Item 2. The processing apparatus according to Item 1. In a processing method for processing a workpiece by pressing a tool that rotates or vibrates against the workpiece held by a holding means,
The cooled superconductor is housed and fixed in a heat-insulated container installed on a rotating table or a vibration table that is driven to rotate,
A magnet functioning as the tool is disposed adjacent to the superconductor, and the magnet is moved from the superconductor to a certain height by using the pinning effect of the superconductor during processing operation. Driving the magnet following the superconductor that is driven to rotate or vibrate while staying in position and floating,
At least one of the workpiece and the superconductor is configured to be movable in at least one of a horizontal plane direction parallel to the superconductor surface and a vertical direction perpendicular to the horizontal plane;
A processing method for processing the workpiece by controlling feeding of at least one of the workpiece and the superconductor.

Images